10icud Abstract Template

The aim of a sensitivity analysis is the exploration of changes in model output induced by changes in model input. Such analysis was used in a multitude of papers and case studies to improve the understanding of model behaviour. The novelty of this paper is that the pictorial power of the Geo Information System (GIS) technology is used to display sensitive parameters for combined sewer models taking into account different applications. Results of this study are maps of parameter sensitivities, divided in four applications: 1) uncertainty maps that display regions with high potential for producing model result uncertainties; 2) calibration maps that reveal regions for putting excessive effort into both measurement and calibration of parameters; 3) vulnerability maps, indicating the consequence in case of a system failure; 4) design maps that indicate elements of the system where an increase of capacity results into a valuable improvement. The aim of this article is to highlight advantages and constrains of such GIS based applications of sensitivity analysis for combined sewer models. As conclusion, it was demonstrated, that for all applications, GIS-processing is useful for analyzing and discussing the sensitivity of model parameters and its spatial dimension to get a comprehensive view of the combined sewer system.